Preparation and characterization of mechanical property and permeability of 3D printed composite porous material
In chemical process engineering metallic porous material is a kind of support for membrane and catalyst. Using conventional methods such as tape casting and sintering of metal particles, the geometry of porous substrates is restricted to planar or tubular. However, advanced geometries of the porous material such as microchannels with porous walls etc. are promising for intensifying chemical processes by adapting e.g. the flow profile to the needs of the application.
In addition, for any practical applications, porous structures have to be combined with dense metallic parts, e.g. the chemical reactor wall. The combination of porous and dense structures requires additional process steps such as laser beam welding/brazing which may destroy the porous structure because of excessive energy input. A potential way to simplify the process is using 3D printing – e.g. selective laser melting (SLM) – to print porous structures of advanced geometries and dense structures at same time.
However, to the best of our knowledge, there is no systematic study on the combination of dense and porous part by SLM of metallic powder. At IMVT first promising results on the combination of porous and dense parts realized within single printed pieces were achieved by systematically adjusting several printing parameters. The objective of this thesis is to correlate certain printing parameters to the properties of the resulting porous structure in terms of mean pore size and their distribution, mechanical strength and outer surface properties.
This work includes following tasks:
Literature research on 3D printing porous structure, characterization of porous material, simulation models of porous structure and analysis of the permeation data;
Investigation of the relation between 3D printing parameters (Scan direction, modification, lens position, hatch distance) and mechanical and porous properties. Therefore test specimen will be printed by selective laser melting (SLM) with systematically varied printing parameters. The specimen will be characterized by means of
Morphology (e.g. SEM, 3D profilometry)
Permeation (permeation test set-up)
Mechanical properties (tensile, bending and shearing test at a neighboring institute)
Based on the data obtained, structural parameters such as porosity, pore size (distribution) will be deduced by adapting correlations from literature (e.g. Kozeny-Carman) and – if applicable – correlated to the printing process parameters
The progress of this work will be regularly discussed within the two-weekly meeting of the group “catalytically active coatings” and with the examinator Prof. R. Dittmeyer. After 50% of the thesis work, a half time presentation in the CCT group meeting is expected. The final results of the work are to be presented within the seminar at IMVT (20/30 minutes oral presentation for BSc/MSc) and by a written thesis not exceeding 40 pages for bachelor thesis or 60 pages for master thesis (excluding appendix).
Knowledge in chemical engineering or material science.
Duration: 3 months for bachelor thesis and 6 months for master thesis
Starting date: a.s.a.p.
Examiner: Prof. Dr. Roland Dittmeyer
Supervisor: M.Sc. Dongxu Xie
Contact: dongxu xie Tel. +49 (0)721 -/608-26817 ∂kit edu